Resveratrol has anabolic effects on disc degeneration in a rabbit model

Mitochondrial 'Birth-Death' coordinator: An intelligent hydrogen nanogenerator to enhance intervertebral disc regeneration

Currently, mitochondrial dysfunction caused by oxidative stress is a growing concern in degenerative diseases, notably intervertebral disc degeneration (IVDD). Dysregulation of the balance of mitochondrial quality control (MQC) has been considered the key contributor, while it's still challenging to effectively harmonize different MQC components in a simple and biologically safe way. Hydrogen gas (H2) is a promising mitochondrial therapeutic molecule due to its bio-reductivity and diffusibility across cellular membranes, yet its relationship with MQC regulation remains unknown. Herein, we propose a mitochondrial 'Birth-Death' coordinator achieved by an intelligent hydrogen nanogenerator (Fe@HP-OD), which can sustainably release H2 in response to the unique microenvironment in degenerated IVDs. Both in vitro and in vivo results prove alleviation of cellular oxidative stress and restoration of nucleus pulposus cells function, thereby facilitating successful IVD regeneration. Significantly, this study for the first time proposes the mitochondrial 'Birth-Death' coordination mechanism: 1) attenuation of overactivated mitochondrial 'Death' process (UPRmt and unselective mitophagy); and 2) activation of Adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling pathway for mitochondrial 'Birth-Death' balance (mitochondrial biogenesis and controlled mitophagy). These pioneering findings can fill in the gaps in molecular mechanisms for H2 regulation on MQC homeostasis, and pave the way for future strategies towards restoring equilibrium of MQC system against degenerative diseases.

Current Therapeutic Strategies of Intervertebral Disc Regenerative Medicine

Intervertebral disc degeneration (IDD) is one of the most frequent causes of low back pain. No treatment is currently available to delay the progression of IDD. Conservative treatment or surgical interventions is only used to target the symptoms of IDD rather than treat the underlying cause. Currently, numerous potential therapeutic strategies are available, including molecular therapy, gene therapy, and cell therapy. However, the hostile environment of degenerated discs is a major problem that has hindered the clinical applicability of such approaches. In this regard, the design of drugs using alternative delivery systems (macro-, micro-, and nano-sized particles) may resolve this problem. These can protect and deliver biomolecules along with helping to improve the therapeutic effect of drugs via concentrating, protecting, and prolonging their presence in the degenerated disc. This review summarizes the research progress of diagnosis and the current options for treating IDD.

Reviving Intervertebral Discs: Treating Degeneration Using Advanced Delivery Systems

Intervertebral disc degeneration (IVDD) is commonly associated with many spinal problems, such as low back pain, and significantly impacts a patient's quality of life. However, current treatments for IVDD, which include conservative and surgical methods, are limited in their ability to fully address degeneration. To combat IVDD, delivery-system-based therapy has received extensive attention from researchers. These delivery systems can effectively deliver therapeutic agents for IVDD, overcoming the limitations of these agents, reducing leakage and increasing local concentration to inhibit IVDD or promote intervertebral disc (IVD) regeneration. This review first briefly introduces the structure and function of the IVD, and the related pathophysiology of IVDD. Subsequently, the roles of drug-based and bioactive-substance-based delivery systems in IVDD are highlighted. The former includes natural source drugs, nonsteroidal anti-inflammatory drugs, steroid medications, and other small molecular drugs. The latter includes chemokines, growth factors, interleukin, and platelet-rich plasma. Additionally, gene-based and cell-based delivery systems are briefly involved. Finally, the limitations and future development of the combination of therapeutic agents and delivery systems in the treatment of IVDD are discussed, providing insights for future research.

Pathogenesis and therapeutic implications of matrix metalloproteinases in intervertebral disc degeneration: A comprehensive review

Intervertebral disc (IVD) degeneration (IDD) is a common disorder that affects the spine and is a major cause of lower back pain (LBP). The extracellular matrix (ECM) is the structural foundation of the biomechanical properties of IVD, and its degradation is the main pathological characteristic of IDD. Matrix metalloproteinases (MMPs) are a group of endopeptidases that play an important role in the degradation and remodeling of the ECM. Several recent studies have shown that the expression and activity of many MMP subgroups are significantly upregulated in degenerated IVD tissue. This upregulation of MMPs results in an imbalance of ECM anabolism and catabolism, leading to the degradation of the ECM and the development of IDD. Therefore, the regulation of MMP expression is a potential therapeutic target for the treatment of IDD. Recent research has focused on identifying the mechanisms by which MMPs cause ECM degradation and promote IDD, as well as on developing therapies that target MMPs. In summary, MMP dysregulation is a crucial factor in the development of IDD, and a deeper understanding of the mechanisms involved is needed to develop effective biological therapies that target MMPs to treat IDD.

Intervertebral disc degeneration-Current therapeutic options and challenges

Degeneration of the intervertebral disc (IVD) is a normal part of aging. Due to the spine's declining function and the development of pain, it may affect one's physical health, mental health, and socioeconomic status. Most of the intervertebral disc degeneration (IVDD) therapies today focus on the symptoms of low back pain rather than the underlying etiology or mechanical function of the disc. The deteriorated disc is typically not restored by conservative or surgical therapies that largely focus on correcting symptoms and structural abnormalities. To enhance the clinical outcome and the quality of life of a patient, several therapeutic modalities have been created. In this review, we discuss genetic and environmental causes of IVDD and describe promising modern endogenous and exogenous therapeutic approaches including their applicability and relevance to the degeneration process.

Pharmacological Effects of Resveratrol in Intervertebral Disc Degeneration: A Literature Review

Intervertebral disc degeneration (IDD) is a high incidence disease of musculoskeletal system that often leads to stenosis, instability, pain and even deformity of the spinal segments. IDD is an important cause of discogenic lower back pain and often leads to large economic burden to families and society. Currently, the treatment of IDD is aimed at alleviating symptoms rather than blocking or reversing pathological progression of the damaged intervertebral disc. Resveratrol (RSV) is a polyphenol phytoalexin first extracted from the Veratrum grandiflflorum O. Loes and can be found in various plants and red wine. Owing to the in-depth study of pharmacological mechanisms, the therapeutic potential of RSV in various diseases such as osteoarthritis, neurodegenerative diseases, cardiovascular diseases and diabetes have attracted the attention of many researchers. RSV has anti-apoptotic, anti-senescent, anti-inflammatory, anti-oxidative, and anabolic activities, which can prevent further degeneration of intervertebral disc cells and enhance their regeneration. With high safety and various biological functions, RSV might be a promising candidate for the treatment of IDD. This review summarizes the biological functions of RSV in the treatment of IDD and to facilitate further research.

Antioxidant Effects of Resveratrol in Intervertebral Disk

Intervertebral disk (IVD) degeneration (IVDD) can cause various spinal degenerative diseases. Cumulative evidence has indicated that IVDD can result from inflammation, apoptosis, autophagy, biomechanical changes and other factors. Currently, lack of conservative treatment for degenerative spinal diseases leads to an urgent demand for clinically applicable medication to ameliorate the progression of IVDD. Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a polyphenol compound extracted from red wine or grapes, has shown protective effects on IVD, alleviating the progression of IVDD. Resveratrol has been demonstrated as a scavenger of free radicals both in vivo and in vitro. The antioxidant effects of resveratrol are likely attributed to its regulation on mitochondrial dysfunction or the elimination of reactive oxygen species. This review will summarize the mechanisms of the reactive oxygen species production and elaborate the mechanisms of resveratrol in retarding IVDD progression, providing a comprehensive understanding of the antioxidant effects of resveratrol in IVD.

Effects of vertebral fusion on levels of pro-inflammatory and catabolic mediators in a rabbit model of intervertebral disc degeneration

OBJECTIVE

The aim of this study was to explore the alterations in levels of pro-inflammatory and catabolic mediators following vertebral fusion in a rabbit model of intervertebral disc degeneration.

METHODS

In this study, 24 female New Zealand albino rabbits (aged 4 to 5 months and weighing 3 to 3.5 kg) were used. All the animals were randomly categorized into four groups, and dorsal spinal exposure of all lumbar vertebrae was routinely performed in each group. While disc degeneration was created in groups B, C, and D, spinal fusion was added to disc degeneration in groups C and D. Disc degeneration was typically created by puncturing the discs with an 18-gauge needle under the guidance of C-arm imaging. Fusion was achieved with posterior/posterolateral decortication and iliac bone grafts. The rabbits in groups A, B, and C were euthanized, and the discs were removed in the first week after the surgery. The rabbits in Group D were sacrificed, and the discs were harvested at 5 weeks after the surgery. The levels of Interleukin (IL)-1β, IL-6, Nitric Oxide (NO), Matrix Metalloproteinase (MMP)-3, MMP-13, and Tissue Inhibitor of Metalloproteinases-1 (TIMP-1) in the discs were analyzed using enzyme-linked immunosorbent assay kits.

RESULTS

Significant increase was observed in the protein levels of both pro-inflammatory and catabolic mediators in disc degeneration groups (Group B, C, and D) compared to Group A. In the fusion groups (Group C and D), these increased mediators decreased, compared to non-fusion group (Group B), (IL1-β P = 0.017, TIMP-1 P = 0.03, NO P = 0.03). However, there was no statistically significant difference in mediator levels between the short- and long-term fusion (Group C versus D).

CONCLUSION

The results of this study have shown that a significant decrease in pro-inflammatory and catabolic mediators may be expected after vertebral fusion whereas there may be no significant difference between the first and fourth week of fusion surgery. These findings may contribute to clarifying the mechanism of action of vertebral fusion in the treatment of low back pain.

Small molecule-based treatment approaches for intervertebral disc degeneration: Current options and future directions

Low back pain (LBP) is a major reason for disability, and symptomatic intervertebral disc (IVD) degeneration (IDD) contributes to roughly 40% of all LBP cases. Current treatment modalities for IDD include conservative and surgical strategies. Unfortunately, there is a significant number of patients in which conventional therapies fail with the result that these patients remain suffering from chronic pain and disability. Furthermore, none of the current therapies successfully address the underlying biological problem - the symptomatic degenerated disc. Both spinal fusion as well as total disc replacement devices reduce spinal motion and are associated with adjacent segment disease. Thus, there is an unmet need for novel and stage-adjusted therapies to combat IDD. Several new treatment options aiming to regenerate the IVD are currently under investigation. The most common approaches include tissue engineering, growth factor therapy, gene therapy, and cell-based treatments according to the stage of degeneration. Recently, the regenerative activity of small molecules (low molecular weight organic compounds with less than 900 daltons) on IDD was demonstrated. However, small molecule-based therapy in IDD is still in its infancy due to limited knowledge about the mechanisms that control different cell signaling pathways of IVD homeostasis. Small molecules can act as anti-inflammatory, anti-apoptotic, anti-oxidative, and anabolic agents, which can prevent further degeneration of disc cells and enhance their regeneration. This review pursues to give a comprehensive overview of small molecules, focusing on low molecular weight organic compounds, and their potential utilization in patients with IDD based on recent in vitro, in vivo, and pre-clinical studies.

Resveratrol Combined with 17β-Estradiol Prevents IL-1β Induced Apoptosis in Human Nucleus Pulposus Via The PI3K/AKT/Mtor and PI3K/AKT/GSK-3β Pathway

BACKGROUNDS

Nucleus pulposus (NP) apoptosis is mainly charged for the pathological process of Intervertebral disc degeneration (IVDD). Our previous study revealed that Resveratrol (RSV) combined with 17β-estradiol (E2) was more effective in cutting down IL-1β induced NP cell apoptosis via PI3K/AKT pathway. The present study further evaluated the effect of RSV and E2 in the anti-apoptosis process of IVDD.

METHODS

Human nucleus pulposus (NP) cells culture system and IL-1β inducing apoptosis model were constructed in this research. RSV and E2 were used to inhibit apoptosis. FACS (Fluorescence-activated cell sorting) and CCK-8 (Cell Counting Kit-8) assays were respectively used to determine apoptotic incidence and cell viability of NP cells. Quantitative RT-PCR was used to determine expression of target genes in mRNA level, and western blot analysis was performed to detect the changes of related protein expression.

RESULTS

RSV combined with E2 attenuated IL-1β-induced cell apoptosis and recovered cell viability. Blockers for mTOR and GSK-3β abated the effect of RSV and E2. RSV combined with E2 obviously increased activated P-mTOR and P-GSK-3β, which contributes to the downregulation of caspase-3. Activated P-NF-kappa B was not involved in the anti-apoptosis process of RSV and E2.

CONCLUSION

Combination of Resveratrol and 17β-estradiol efficiently resisted IL-1β induced apoptosis of NP cell, mainly through PI3K/AKT/mTOR/caspase-3 and PI3K/AKT/GSK-3β pathway.

Resveratrol inhibits IL-1β-mediated nucleus pulposus cell apoptosis through regulating the PI3K/Akt pathway

Nucleus pulposus (NP) cell apoptosis is a classical cellular character during intervertebral disc degeneration (IDD). Previous studies have shown that inflammatory cytokine-induced NP cell apoptosis plays an important role in disc degeneration. The present study was aimed to investigate whether resveratrol can suppress IL-1β-mediated NP cell apoptosis and the potential signal transduction pathway. Experimental rat NP cells were treated with culture medium containing IL-1β (20 ng/ml) for 7 days. Control NP cells were cultured in the baseline medium. Resveratrol was added along with culture medium to investigate its effects. The inhibitor LY294002 was used to study the role of the PI3K/Akt pathway. NP cell apoptosis was reflected by the caspase-3 activity, cell apoptosis ratio, and expression of apoptosis-related molecules (Bcl-2, Bax, caspase-3, cleaved caspase-3, and cleaved PARP). Compared with the control NP cells, IL-1β significantly increased caspase-3 activity, NP cell apoptosis ratio and mRNA/protein expression of Bax, caspase-3, cleaved caspase-3 and cleaved PARP, but decreased mRNA expression of Bcl-2. However, resveratrol partly suppressed the effects of IL-1β on those cell apoptosis-related parameters. Further analysis showed that IL-1β significantly decreased activity of the PI3K/Akt pathway whereas resveratrol partly increased activity of the PI3K/Akt pathway in NP cells treated with IL-1β. Additionally, when the inhibitor LY294002 was added along with the resveratrol, its protective effects against IL-1β-induced NP cell apoptosis were attenuated. In conclusion, resveratrol suppresses IL-1β-mediated NP cell apoptosis through activating the PI3K/Akt pathway. Resveratrol may be an effective drug to attenuate inflammatory cytokine-induced disc degenerative changes.

A Histopathological Scheme for the Quantitative Scoring of Intervertebral Disc Degeneration and the Therapeutic Utility of Adult Mesenchymal Stem Cells for Intervertebral Disc Regeneration

The purpose of this study was to develop a quantitative histopathological scoring scheme to evaluate disc degeneration and regeneration using an ovine annular lesion model of experimental disc degeneration. Toluidine blue and Haematoxylin and Eosin (H&E) staining were used to evaluate cellular morphology: (i) disc structure/lesion morphology; (ii) proteoglycan depletion; (iii) cellular morphology; (iv) blood vessel in-growth; (v) cell influx into lesion; and (vi) cystic degeneration/chondroid metaplasia. Three study groups were examined: 5 × 5 mm lesion; 6 × 20 mm lesion; and 6 × 20 mm lesion plus mesenchymal stem cell (MSC) treatment. Lumbar intervertebral discs (IVDs) were scored under categories (i-vi) to provide a cumulative score, which underwent statistical analysis using STATA software. Focal proteoglycan depletion was associated with 5 × 5 mm annular rim lesions, bifurcations, annular delamellation, concentric and radial annular tears and an early influx of blood vessels and cells around remodeling lesions but the inner lesion did not heal. Similar features in 6 × 20 mm lesions occurred over a 3-6-month post operative period. MSCs induced a strong recovery in discal pathology with a reduction in cumulative histopathology degeneracy score from 15.2 to 2.7 (p = 0.001) over a three-month recovery period but no recovery in carrier injected discs.

Hyaluronan oligosaccharides stimulate matrix metalloproteinase and anabolic gene expression in vitro by intervertebral disc cells and annular repair in vivo

The role of hyaluronan (HA) oligosaccharides in disc cell-mediated matrix metalloproteinase (MMP) and anabolic gene expression in vitro and annular repair in vivo were examined. Monolayer and alginate bead cultures of ovine intervertebral disc cells were stimulated with 10-12 mer hyaluronan oligosaccharides (HA-oligos). Annulus fibrosus (AF) monolayers were poorly responsive to the HA-oligos, proMMP-2 levels were marginally elevated and levels were MMP-9 unaffected. ProMMP-2 displayed a strong dose-dependent increase in the nucleus pulposus (NP) monolayers. In AF alginate bead cultures, proMMP-2 and active MMP-9 increased up to day 10, in NP cultures proMMP-2 was progressively converted to active MMP-2 over days 7-10 and active MMP-9 levels were elevated on day 10. A steady decline in MMP-2 and MMP-9 activity was evident over days 2-10 in the non-stimulated NP cultures. Disc cell viabilities were ≥92 ± 5% in all cultures indicating that the HA-oligo was not cytotoxic. Reverse-transcription polymerase chain reaction demonstrated an upregulation in MMP1, MMP113 and ADAMTS1 and the anabolic matrix repair genes ACAN, COL1A1 and COL2A1 in the NP by HA-oligos, whereas AF MMP13, ADAMTS1, ADAMTS4 and ADAMTS5, ACAN and COL2A1 were down-regulated; this differential regulation is expected to promote clearance of granulation/scar tissue from AF defects and matrix replenishment. The AF defect sites contained enlarged annular lamellae in vivo in response to the HA oligos, which is consistent with an active repair response. Masson trichrome and PicroSirius red histology and immunolocalization of type I collagen supported active remodelling in the outer lesion zone by the HA-oligo treatment but not the inner lesion. Copyright © 2016 John Wiley & Sons, Ltd.

Effect of Resveratrol on Preventing Steroid-induced Osteonecrosis in a Rabbit Model

Background:

Prevention of osteonecrosis (ON) has seldom been addressed. The purpose of this study was to evaluate the effect of resveratrol on preventing steroid-induced ON in rabbits.

Methods:

Seventy-two rabbits were divided into four groups: (1) NEC (ON) group: thirty rabbits were treated with lipopolysaccharide (LPS) once, then with methylprednisolone (MPS) daily for 3 days; (2) PRE (prevention) group: thirty rabbits were given one dose of LPS, then MPS daily for 3 days, and resveratrol on day 0 and daily for 2 weeks; (3) RES (resveratrol) group: six rabbits were given resveratrol for 2 weeks but without LPS/MPS; (4) CON (control) group: six rabbits were given alcohol for 2 weeks but without LPS/MPS. Levels of plasma tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor 1 (PAI-1), thrombomodulin (TM), vascular endothelial growth factor (VEGF), maximum enhancement (ME) by magnetic resonance imaging, and ON incidence were evaluated.

Results:

The PRE group had a lower ON incidence than the NEC group, but with no significant differences at 2 weeks and 12 weeks. The RES and CON groups did not develop ON. TM and VEGF were significantly higher in the NEC group compared with the PRE group at weeks 1, 2, and 4 (TM: 1 week, P = 0.029; 2 weeks, P = 0.005; and 4 weeks, P = 0.047; VEGF: 1 week, P = 0.039; 2 weeks, P = 0.021; 4 weeks, P = 0.014), but the difference disappeared at 12 weeks. The levels of t-PA and PAI-1 were not significantly different between the NEC and PRE groups. The TM, t-PA, PAI-1, and VEGF concentrations in the RES and CON groups did not change over time. Compared to the baseline, ME in the NEC group decreased significantly (P = 0.025) at week 1, increased significantly (P = 0.021) at week 2, and was decreased at week 12. The variance was insignificant in the PRE group.

Conclusions:

Resveratrol may improve blood supply to bone in a rabbit model of ON of the femoral head via anti-inflammatory effects to protect the vascular endothelium and reduce thrombosis.

Combined effect of 17β-estradiol and resveratrol against apoptosis induced by interleukin-1β in rat nucleus pulposus cells via PI3K/Akt/caspase-3 pathway

Background: In previous studies, both 17β-estradiol (E2) and resveratrol (RES) were reported to protect intervertebral disc cells against aberrant apoptosis. Given that E2 has a better anti-apoptotic effect with more cancer risk and RES has an anti-apoptotic effect with less cancer risk, the combined use of E2 with RES is promising in developing clinical therapies to treat apoptosis-related diseases such as intervertebral disc degeneration in the future. Objective: The purpose of this study was to explore the combined effect of E2 with RES on rat nucleus pulposus cells and the underlying mechanisms. Methods: TUNEL assay and FACS analysis were used to determine apoptotic incidence of nucleus pulposus cells. MTS assay was used to determine cell viability, and cellular binding assay was used to determine cell-ECM (extracellular matrix) ability. Real-time quantitative RT-PCR was to determine mRNA level of target genes. And Western blot was used to determine the protein level. Results: Both E2 and RES decreased apoptotic incidence when used singly; interestingly, they decreased apoptosis more efficiently when used combinedly. Meanwhile, E2 and RES combined together against the decrease of cell viability and binding ability resulting from IL-1β cytotoxicity. As well, activated caspase-3 was suppressed by the combined effect. Furthermore, IL-1β downregulated expression level of type II collagen and aggrecan (standing for anabolism), while upregulated MMP-3 and MMP-13 (standing for catabolism). However, the combined use of E2 with RES effectively abolished the above negative effects caused by IL-1β, better than either single use. Finally, it turned out to be that E2 and RES combined together against apoptosis via the activation of PI3K/Akt/caspase-3 pathway. Conclusion: This study presented that IL-1β induced aberrant apoptosis, which was efficiently resisted by the combined use of E2 with RES via PI3K/Akt/caspase-3 pathway.

SIRT1 Plays a Protective Role in Intervertebral Disc Degeneration in a Puncture-induced Rodent Model

STUDY DESIGN

Experimental animal study of treatment of intervertebral disc (IVD) degeneration.

OBJECTIVE

This report aims to evaluate the in vivo effects of SIRT1 on IVD biology and to explore its potential mechanism.

SUMMARY OF BACKGROUND DATA

Silent mating type information regulator 2 homolog 1 (SIRT1) has attracted immense attention because of its functions in a variety of aging-related diseases. Despite previous studies indicated that SIRT1 showed a unique expression with degeneration in some in vitro study, there is no in vivo research on the role SIRT1 plays in IVD and its mechanism.

METHODS

Coccygeal discs were punctured to induce disc degeneration. Sixteen C57BL/6J mice received either Carboxy methocel (Vehicle) or Resveratrol (RES) gavage. Eight SIRT1 mice and their SIRT1 littermates were also used in this study. At 2 and 6 weeks after puncture, magnetic resonance images were obtained. The mice were subsequently killed, and the spine was extracted for further evaluation.

RESULTS

Coccygeal disc puncture caused IVD degeneration in the mice. A SIRT1 activator, RES, markedly ameliorated this pathological change, as demonstrated by stronger signal intensity in the T2-weighted images, as well as a significantly lower magnetic resonance imaging grade (at 2 wk vs. Vehicle group P < 0.001). Histological analysis also revealed an improvement in the RES group compared with the Vehicle group (P < 0.05). Genetic ablation of 1 allele significantly enhanced the level of damage relative to the wild-type mice. In addition, SIRT1 activation suppressed the expression of p16 and at the same time, promoted proliferating cell nuclear antigen and type II collagen expression in disc cells, whereas genetic ablation of 1 allele SIRT1 exhibited the opposite consequence.

CONCLUSION

The SIRT1 activator RES protects against puncture-induced disc injury whereas SIRT1 deficiency aggravates tissue injury; the protective role of SIRT1 is partly mediated by suppressing p16, which plays a role in elevating the decreased proliferative ability of the senescent nucleus pulposus cells.

LEVEL OF EVIDENCE

N/A.